High voltage pumping circuit

ABSTRACT

A swing width control circuit and a high voltage pumping circuit using the same are disclosed. The swing width control circuit includes a swing width controller for receiving a first pumping signal having a first swing width and generating a second pumping signal having a second swing width larger than the first swing width of the first pumping signal, in accordance with a level of a supply voltage to pump or precharge a voltage of a specific node, and a swing width holding device for maintaining a swing width of the specific node to be equal to the second swing width of the second pumping signal.

This application is a divisional of U.S. Ser. No. 11/497,860, filed Aug.1, 2006 now U.S. Pat. No. 7,576,590, which claims priority of KoreanPatent Application No. 10-2006-0027438, filed Mar. 27, 2006, thecontents of which are hereby incorporated by reference into thisapplication.

TECHNICAL FIELD

The present disclosure relates to a high voltage pumping circuit, andmore particularly to a swing width control circuit for, when a supplyvoltage VDD is relatively low, significantly increasing the swing widthof a pumping signal for a pumping operation for generation of a highvoltage VPP, so that pumping capability can be improved under thecondition of the low supply voltage VDD, and a high voltage pumpingcircuit using the same.

BACKGROUND

In general, a dynamic random access memory (DRAM) is a memory deviceincluding a plurality of memory cells, each of which is composed of onetransistor and one capacitor. In this DRAM, data can be written into orread from each memory cell and a high voltage VPP is required to driveword lines. This high voltage VPP is generated by a high voltagegeneration circuit in consideration of a supply voltage VDD andthreshold voltage Vth of a MOS transistor constituting the celltransistor. The high voltage generation circuit includes an oscillationcircuit, a charge pumping circuit, etc. The oscillation circuit isoperated in response to an enable signal to generate an oscillationsignal with a certain period, and the charge pumping circuit pumps thesupply voltage VDD, which is an external voltage, in response to theoscillation signal to generate the high voltage VPP.

In a memory device having a low supply voltage VDD of about 1.8V, thehigh voltage VPP is on the order of 3 to 4V. The high voltage VPP ishigher than the supply voltage VDD and is generated by pumping thesupply voltage VDD using the pumping circuit. In particular, in the casewhere the supply voltage VDD is low, a high voltage pumping circuit suchas a VPP tripler is used because it is difficult to generate the highvoltage VPP by pumping the low supply voltage VDD.

SUMMARY

Therefore, the present disclosure provides a number of examples of aswing width control circuit for, when a supply voltage VDD is relativelylow, significantly increasing the swing width of a pumping signal for apumping operation for generation of a high voltage VPP, so that pumpingcapability can be improved under the condition of the low supply voltageVDD, and a high voltage pumping circuit using the same.

In an embodiment of the present disclosure, there is provided a highvoltage pumping circuit comprising: a first pumping circuit including aprecharge circuit for precharging a first node, a first swing widthcontroller for outputting a pumping signal for pumping of a voltage ofthe first node, and a first swing width holding device for maintaining aswing width of the first node to be equal to that of the pumping signalfrom the first swing width controller; a second pumping circuitincluding a first precharge device for precharging a second node inresponse to a signal from the first node, a second swing widthcontroller for outputting a pumping signal for pumping of a voltage ofthe second node, and a second swing width holding device for maintaininga swing width of the second node to be equal to that of the pumpingsignal from the second swing width controller; and a first transferdevice for transferring the voltage of the second node in response to afirst transfer control signal, wherein each of the first and secondswing width controllers receives a first pumping signal having a firstswing width and generates a second pumping signal having a second swingwidth larger than the first swing width of the first pumping signalaccording to a level of a supply voltage.

The high voltage pumping circuit may further comprise: a third pumpingcircuit including a second precharge device for precharging a third nodein response to the signal from the first node, a third swing widthcontroller for outputting a pumping signal for pumping of a voltage ofthe third node, and a third swing width holding device for maintaining aswing width of the third node to be equal to that of the pumping signalfrom the third swing width controller; and a first control signalgenerator including a third precharge device for precharging a fourthnode in response to the signal from the first node, a first swing widthchanger for changing a swing width of a signal from the third node, anda fourth swing width holding device for maintaining a swing width of thefourth node to be equal to that of an output signal from the first swingwidth changer to generate the first transfer control signal, wherein thethird swing width controller receives the first pumping signal havingthe first swing width and generates the second pumping signal having thesecond swing width larger than the first swing width of the firstpumping signal according to the level of the supply voltage.

The first swing width changer may output a signal swinging between aground voltage and a high-level voltage of the signal from the thirdnode.

Preferably, the first swing width changer comprises: a pull-up deviceconnected between the third node and a fifth node, the pull-up devicepulling the fifth node up in response to the supply voltage; and apull-down device connected between the fifth node and a ground voltage,the pull-down device pulling the fifth node down in response to anenable signal.

Preferably, each of the first to third swing width controllerscomprises: a supply voltage detector for generating a control signalhaving a first level when the supply voltage is higher than or equal toa predetermined reference voltage and a second level when the supplyvoltage is lower than the reference voltage; and a swing width selectorfor receiving the control signal and the first pumping signal andoutputting the first pumping signal when the control signal has thefirst level and the second pumping signal when the control signal hasthe second level.

Preferably, the swing width selector comprises: a signal input unit forpulling a fifth node up and transferring the first pumping signal to asixth node, when the control signal has the first level, andtransferring the first pumping signal to the fifth node when the controlsignal has the second level; and a signal processor connected betweenthe fifth node and the sixth node, the signal processor generating thesecond pumping signal and outputting it to the sixth node, when thefirst pumping signal is transferred to the fifth node.

Preferably, the signal input unit comprises: first and second transfergates selectively turned on in response to the control signal; and apull-up device for pulling the fifth node up in response to the controlsignal, wherein the first transfer gate transfers the first pumpingsignal to the fifth node and the second transfer gate transfers thefirst pumping signal to the sixth node.

Preferably, the signal processor comprises: a first capacitor connectedbetween the fifth node and a seventh node; a buffer connected to thefifth node; a second capacitor connected between an output terminal ofthe buffer and an eighth node; a first pull-up device connected betweenthe seventh node and the supply voltage, the first pull-up devicepulling the seventh node up in response to a signal from the eighthnode; a second pull-up device connected between the eighth node and thesupply voltage, the second pull-up device pulling the eighth node up inresponse to a signal from the seventh node; a first transistor connectedbetween the eighth node and a ninth node, the first transistor beingturned on in response to a signal from the fifth node; and a thirdcapacitor connected between the ninth node and the sixth node.

The first pull-up device and the second pull-up device may be NMOStransistors and the first transistor may be a PMOS transistor.

The signal processor may further comprise a second transistor connectedbetween the ninth node and a ground voltage, the second transistor beingturned on in response to the signal from the fifth node.

The second swing width may be set to twice the first swing width.

The first to fourth swing width holding devices may be capacitors.

Preferably, the precharge circuit comprises: a fourth precharge deviceconnected between the supply voltage and the first node, the fourthprecharge device precharging the first node in response to the supplyvoltage; and a fifth precharge device connected between the supplyvoltage and the first node, the fifth precharge device precharging thefirst node in response to the signal from the third node.

The high voltage pumping circuit may further comprise: a fourth pumpingcircuit including a fourth swing width controller for outputting apumping signal for pumping of a voltage of a fifth node to which thevoltage of the second node is transferred through the first transferdevice, and a fifth swing width holding device for maintaining a swingwidth of the fifth node to be equal to that of the pumping signal fromthe fourth swing width controller; and a second transfer device fortransferring the voltage of the fifth node in response to a secondtransfer control signal, wherein the fourth swing width controllerreceives the first pumping signal having the first swing width andgenerates the second pumping signal having the second swing width largerthan the first swing width of the first pumping signal when the supplyvoltage is lower than a predetermined reference voltage.

The high voltage pumping circuit may further comprise: a fifth pumpingcircuit including a fourth precharge device for precharging a sixth nodein response to a signal from the fourth node, a fifth swing widthcontroller for outputting a pumping signal for pumping of a voltage ofthe sixth node, and a sixth swing width holding device for maintaining aswing width of the sixth node to be equal to that of the pumping signalfrom the fifth swing width controller; and a second control signalgenerator including a fifth precharge device for precharging a seventhnode in response to the signal from the fourth node, a second swingwidth changer for changing a swing width of a signal from the sixthnode, and a seventh swing width holding device for maintaining a swingwidth of the seventh node to be equal to that of an output signal fromthe second swing width changer to generate the second transfer controlsignal.

Preferably, the second swing width changer comprises: a pull-up deviceconnected between the sixth node and an eighth node, the pull-up devicepulling the eighth node up in response to the supply voltage; and apull-down device connected between the eighth node and a ground voltage,the pull-down device pulling the eighth node down in response to anenable signal.

BRIEF DESCRIPTION OF DRAWINGS

The above and other objects, features and other advantages of thepresent disclosure will be more clearly understood from the followingdetailed description taken in conjunction with the accompanyingdrawings, in which:

FIG. 1 is a circuit diagram showing the configuration of a VPP tripleraccording to an exemplary embodiment of the present disclosure;

FIG. 2 is a block diagram of a swing width controller in FIG. 1;

FIG. 3 is a circuit diagram of a swing width selector in FIG. 2; and

FIG. 4 is an output waveform diagram of the VPP tripler according to thepresent disclosure.

DESCRIPTION OF PREFERRED EMBODIMENTS

Reference will now be made in detail to preferred embodiments of thepresent disclosure, examples of which are illustrated in theaccompanying drawings, wherein like reference numerals refer to likeelements throughout. The embodiments are described below to explain thepresent disclosure by referring to the figures.

FIG. 1 is a circuit diagram showing the configuration of a VPP tripleraccording to an exemplary embodiment of the present disclosure, FIG. 2is a block diagram of a swing width controller in FIG. 1, and FIG. 3 isa circuit diagram of a swing width selector in FIG. 2.

Referring to FIG. 1, the VPP tripler according to the present embodimentcomprises a first pumping circuit 10 including a precharge circuit 12for precharging a node a, a first swing width controller 101 foroutputting a pumping signal for pumping of the voltage of the node a,and a capacitor C1 for maintaining the swing width of the node a to beequal to that of the pumping signal from the first swing widthcontroller 101. The VPP tripler according to the present embodimentfurther comprises a second pumping circuit 20 including an NMOStransistor N3 for precharging a node b in response to a signal from thenode a, a second swing width controller 102 for outputting a pumpingsignal for pumping of the voltage of the node b, and a capacitor C2 formaintaining the swing width of the node b to be equal to that of thepumping signal from the second swing width controller 102. The VPPtripler according to this embodiment further comprises an NMOStransistor N5 for transferring the voltage of the node b to a node f inresponse to a first transfer control signal.

The precharge circuit 12 includes an NMOS transistor N1 connectedbetween a supply voltage VDD and the node a and adapted for prechargingthe node a in response to the supply voltage VDD, and an NMOS transistorN2 connected between the supply voltage VDD and the node a and adaptedfor precharging the node a in response to a signal from a node c.

The VPP tripler according to this embodiment further comprises a thirdpumping circuit 30 including an NMOS transistor N7 for precharging thenode c in response to the signal from the node a, a third swing widthcontroller 103 for outputting a pumping signal for pumping of thevoltage of the node c, and a capacitor C4 for maintaining the swingwidth of the node c to be equal to that of the pumping signal from thethird swing width controller 103. The VPP tripler according to thepresent embodiment further comprises a first control signal generator 40including an NMOS transistor NB for precharging a node d in response tothe signal from the node a, a first swing width changer 42 for changingthe swing width of the signal from the node c, and a capacitor C5 formaintaining the swing width of the node d to be equal to that of anoutput signal from the first swing width changer 42 to generate thefirst transfer control signal.

The first swing width changer 42 is adapted to output a signal swingingbetween a ground voltage and a high-level voltage of the signal from thenode c. To this end, the first swing width changer 42 includes a PMOStransistor P1 connected between the node c and a node e and adapted forpulling the node e up in response to the supply voltage VDD, and an NMOStransistor N9 connected between the node e and the ground voltage andadapted for pulling the node e down in response to an enable signalOSCB_T.

The VPP tripler according to the present embodiment further comprises afourth pumping circuit 50 including a fourth swing width controller 104for outputting a pumping signal for pumping of the voltage of the node fto which the voltage of the node b is transferred through the NMOStransistor N5, and a capacitor C3 for maintaining the swing width of thenode f to be equal to that of the pumping signal from the fourth swingwidth controller 104. The VPP tripler according to the presentembodiment further comprises an NMOS transistor NG for transferring thevoltage of the node f in response to a second transfer control signalfrom a node h, and a fifth pumping circuit 60 including an NMOStransistor N11 for precharging a node g in response to a signal from thenode d, a fifth swing width controller 105 for outputting a pumpingsignal for pumping of the voltage of the node g, and a capacitor C6 formaintaining the swing width of the node g to be equal to that of thepumping signal from the fifth swing width controller 105. The VPPtripler according to the present embodiment further comprises a secondcontrol signal generator 70 including an NMOS transistor N10 forprecharging the node h in response to the signal from the node d, asecond swing width changer 72 for changing the swing width of a signalfrom the node g, and a capacitor C7 for maintaining the swing width ofthe node h to be equal to that of an output signal from the second swingwidth changer 72 to generate the second transfer control signal.

The second swing width changer 72 includes a PMOS transistor P2connected between the node g and a node i and adapted for pulling thenode up in response to the supply voltage VDD, and an NMOS transistorN12 connected between the node i and the ground voltage and adapted forpulling the node i down in response to the enable signal OSCB_T.

The configuration of each of the first to fifth swing width controllers101 to 105 will hereinafter be described in detail with reference toFIGS. 2 and 3.

Each of the first to fifth swing width controllers 101 to 105 includes,as shown in FIG. 2, a VDD detector 110 for generating a control signalhaving a low level when the supply voltage VDD is higher than or equalto a predetermined reference voltage Vref and a high level when thesupply voltage VDD is lower than the reference voltage Vref, and a swingwidth selector 120 for receiving the control signal and a first pumpingsignal Vin (PCAP0, PCAP1, PCAP2 or OSC_T) with a swing width of a VDDlevel and providing, as its output signal Vout, the first pumping signalVin when the control signal has the low level and a second pumpingsignal with a swing width of a 2VDD level when the control signal hasthe high level, to pump or precharge the voltage of a specific node. TheVDD detector 110 may be made up of a plurality of transistors connectedin series by using threshold voltages Vth thereof. With thisconfiguration, the VDD detector 110 generates the control signal of thehigh level or low level according to the VDD level.

In FIG. 3, the swing width selector 120 includes a signal input unit 200for pulling a node A up and transferring the first pumping signal Vin toa node E, when the control signal has the low level, and transferringthe first pumping signal Vin to the node A when the control signal hasthe high level, and a signal processor 210 connected between the node Aand the node E and adapted for generating the second pumping signal andoutputting it to the node E, when the first pumping signal Vin istransferred to the node A. In more detail, the signal input unit 200includes first and second transfer gates T1 and T2 selectively turned onin response to the control signal, and a PMOS transistor P20 for pullingthe node A up in response to the low-level control signal. The firsttransfer gate T1 transfers the first pumping signal Vin to the node Aand the second transfer gate T2 transfers the first pumping signal Vinto the node E. The signal processor 210 includes a capacitor C11connected between the node A and a node B, an inverter IV22 connected tothe node A, a capacitor C12 connected between an output terminal of theinverter IV22 and a node C, an NMOS transistor N21 connected between thenode B and the supply voltage VDD and adapted for pulling the node B upin response to a signal from the node C, an NMOS transistor N22connected between the node C and the supply voltage VDD and adapted forpulling the node C up in response to a signal from the node B, a PMOStransistor P21 connected between the node C and a node D and turned onor off in response to a signal from the node A, a capacitor C13connected between the node D and the node E, and an NMOS transistor N23connected between the node D and the ground voltage and turned on or offin response to the signal from the node A.

Preferably, the reference voltage Vref is 1.5V, the pumped high voltageVPP is 2.5˜4V, the high voltage pumping capability of the VPP tripler is0.5˜9 mA/pump, and the VDD voltage detection range of the VDD detector110 is 0.5˜1.5V. In a semiconductor memory device, it is typicallypreferable that VPP current is 1˜100 μA in a standby state and 10 μA˜100μmA in an active state, and the period of a VPP oscillator is 10˜100 ns.Here, the oscillator period may be selectively changed in a test mode orby fuse trimming.

The operation of each of the swing width controllers 101 to 105 of thepresent disclosure will hereinafter be described with reference to FIGS.2 and 3.

First, the VDD detector 110 of each of the swing width controllers 101to 105 detects the supply voltage VDD, compares it with thepredetermined reference voltage Vref and generates the control signalaccording to the comparison result. At this time, the generated controlsignal has the low level when the detected supply voltage VDD is higherthan or equal to the reference voltage Vref and the high level when thesupply voltage VDD is lower than the reference voltage Vref. Here, theVDD detector 110 may be implemented by a voltage detection circuit usedin an existing voltage pumping device.

Then, the control signal generated by the VDD detector 110 is inputtedto the swing width selector 120 along with the first pumping signal Vin(PCAP0, PCAP1, PCAP2 or OSC_T) with the swing width of the VDD level.When the inputted control signal has the high level, namely, the supplyvoltage VDD is lower than the reference voltage Vref, the transfer gateT1 is turned on to transfer the first pumping signal Vin (PCAP0, PCAP1,PCAP2 or OSC_T) to the node A. At this time, the node C of the signalprocessor 210 is set to be precharged to the VDD level, so that thesignal processor 210 outputs the second pumping signal with the swingwidth of the 2VDD level to the node E. That is, when the first pumpingsignal Vin (PCAP0, PCAP1, PCAP2 or OSC_T) assumes a high level (VDD),the node B is given the VDD level by the capacitor C11, which is acharge holding device, under the condition that the PMOS transistor P21is turned off. As a result, the NMOS transistor N22 is turned on,thereby causing the node C to be precharged to the VDD level. At thistime, because the NMOS transistor N23 is turned on, the node D becomeslow in level. Thereafter, at the time that the first pumping signal Vin(PCAP0, PCAP1, PCAP2 or OSC_T) becomes low in level, a signal at theoutput terminal of the inverter IV22 assumes the high level (VDD), sothat the node C is pumped to the 2VDD level by the capacitor C12. Atthis time, because the PMOS transistor P21 is turned on, the voltagelevel of the node D becomes the 2VDD level. In other words, when thehigh-level control signal is inputted, the node D is changed from a lowlevel (ground level) to a high level (2VDD) and this voltage swing widthof the node D is transferred to the node E through the capacitor C13,which is a charge holding device. As a result, the pumping signal Voutoutputted at the node E has the swing width of the 2VDD level. On theother hand, when the inputted control signal has the low level, namely,the supply voltage VDD is higher than or equal to the reference voltageVref, the transfer gate T2 is turned on to transfer the first pumpingsignal Vin (PCAP0, PCAP1, PCAP2 or OSC_T) to the node E. As a result,the first pumping signal Vin (PCAP0, PCAP1, PCAP2 or OSC_T) is outputtedas the pumping signal Vout at the node E. At this time, the PMOStransistor P20 is turned on, thereby causing a high-level DC voltage tobe inputted to the signal processor 210. Thus, the NMOS transistor N23remains on and the node D is maintained at the ground level.

To sum up, each of the swing width controllers 101 to 105 of the presentdisclosure adjusts the swing width of the inputted first pumping signalVin (PCAP0, PCAP1, PCAP2 or OSC_T) to the 2VDD level and outputs theresulting second pumping signal as the pumping signal Vout, when thesupply voltage VDD is lower than the reference voltage Vref, and outputsthe inputted first pumping signal Vin (PCAP0, PCAP1, PCAP2 or OSC_T)directly as the pumping signal Vout when the supply voltage VDD ishigher than or equal to the reference voltage Vref. That is, each of theswing width controllers 101 to 105 of the present disclosure increasesthe swing width of the pumping signal Vout when the supply voltage VDDis low, so that pumping efficiency can be improved under the conditionof the low supply voltage VDD.

Next, the operation of the VPP tripler with the swing width controllers101 to 105 of the present disclosure as stated above will be describedwith reference to FIG. 1.

First, when the supply voltage VDD is lower than the reference voltageVref, the swing width of the first pumping signal Vin (PCAP0, PCAP1,PCAP2 or OSC_T) inputted to each of the swing width controllers 101 to105 of the present disclosure is adjusted to the 2VDD level and theresulting second pumping signal is outputted as the pumping signal Vout.In this case, the VPP tripler is operated in the following manner.

When the supply voltage VDD is applied, the NMOS transistors N1 and N4are turned on, thereby causing the node a and node b to be precharged toa VDD-Vth (a threshold voltage of each NMOS transistor) level. Then,because the swing width controller 101 receives the pumping signal PCAP0with the swing width of the VDD level and outputs the pumping signalVout with the swing width of the 2VDD level, the node a is pumped with aswing width of a 3VDD-Vth level by the capacitor C1 which maintains theswing widths of voltages applied to both ends thereof equal.

Then, the NMOS transistors N3, N7 and N8 are turned on by the pumpedvoltage of the node a, so that the node b, node c and node d areprecharged to the VDD level. At this time, the node b is pumped by thepumping signal with the swing width of the 2VDD level from the swingwidth controller 102 of the second pumping circuit 20, so as to have aswing width of a 3VDD level, and the node c is pumped by the pumpingsignal with the swing width of the 2VDD level from the swing widthcontroller 103, so as to have the swing width of the 3VDD level.Meanwhile, the node a is precharged to the VDD level by the NMOStransistor N2 turned on by the voltage of the node c, and then pumped bythe pumping signal with the swing width of the 2VDD level from the swingwidth controller 101, so as to have the swing width of the 3VDD level.In brief, the node a to node c are precharged to the 3VDD level and thenode d is precharged to the VDD level.

Thereafter, the PMOS transistor P1 is turned on by the signal from thenode c precharged to the 3VDD level, so as to pull the node e up to the3VDD level, and the NMOS transistor N9 is turned on by the enable signalOSCB_T to pull the node e down to the ground level. As a result, thevoltage of the node e has the swing width of the 3VDD level. Also,because the swing width of the node d becomes equal to that of the nodee by the capacitor C5, the voltage of the node d swings from the VDDlevel to a 4VDD level. The NMOS transistor N5 is turned on by thevoltage of the node D which swings in this manner, so as to transfer thevoltage of the node b to the node f, thereby causing the voltage levelof the node f to become the 3VDD level. Thereafter, the node f is pumpedto a 5VDD level by the pumping signal with the swing width of the 2VDDlevel from the swing width controller 104 of the fourth pumping circuit50.

Meanwhile, the NMOS transistors N10 and N11 are turned on by the voltageof the node d pumped to the 4VDD level. As a result, the node g isprecharged to the VDD level, and the voltage of the node f istransferred to the node h, thereby causing the node h to be prechargedto the 3VDD level. At this time, the node g is pumped to the 3VDD levelby the pumping signal with the swing width of the 2VDD level from theswing width controller 105. Then, the PMOS transistor P2 is turned on bythe signal from the node g precharged to the 3VDD level, so as to pullthe node i up to the 3VDD level, and the NMOS transistor N12 is turnedon by the enable signal OSCB_T to pull the node i down to the groundlevel. As a result, the voltage of the node i has the swing width of the3VDD level. Thereafter, the swing width of the node i is transferred tothe node h through the capacitor C7, so that the voltage of the node hswings from the 3VDD level to a 6VDD level. The NMOS transistor N6 isturned on by the voltage of the node h which swings in this manner, soas to transfer the voltage of the 5VDD level of the node f to a node j.Consequently, a high voltage VPP pumped to the 5VDD level is outputtedat the node j.

Next, when the supply voltage VDD is higher than or equal to thereference voltage Vref, the first pumping signal Vin (PCAP0, PCAP1,PCAP2 or OSC_T) inputted to each of the swing width controllers 101 to105 of the present disclosure is outputted directly as the pumpingsignal Vout. In this case, the VPP tripler is operated in the followingmanner.

When the supply voltage VDD is applied, the NMOS transistors N1 and N4are turned on, thereby causing the node a and node b to be precharged tothe VDD-Vth (the threshold voltage of each NMOS transistor) level. Then,because the swing width controller 101 receives the pumping signal PCAP0with the swing width of the VDD level and outputs the pumping signalVout with the swing width of the VDD level, the node a is pumped with aswing width of a 2VDD-Vth level by the capacitor C1 which maintains theswing widths of voltages applied to both ends thereof equal.

Then, the NMOS transistors N3, N7 and N8 are turned on by the pumpedvoltage of the node a, so that the node b, node c and node d areprecharged to the VDD level. At this time, the node b is pumped by thepumping signal with the swing width of the VDD level from the swingwidth controller 102 of the second pumping circuit 20, so as to have theswing width of the 2VDD level, and the node c is pumped by the pumpingsignal with the swing width of the VDD level from the swing widthcontroller 103, so as to have the swing width of the 2VDD level.Meanwhile, the node a is precharged to the VDD level by the NMOStransistor N2 turned on by the voltage of the node c, and then pumped bythe pumping signal with the swing width of the VDD level from the swingwidth controller 101, so as to have the swing width of the 2VDD level.In brief, the node a to node c are precharged to the 2VDD level and thenode d is precharged to the VDD level.

Thereafter, the PMOS transistor P1 is turned on by the signal from thenode c precharged to the 2VDD level, so as to pull the node e up to the2VDD level, and the NMOS transistor N9 is turned on by the enable signalOSCB_T to pull the node e down to the ground level. As a result, thevoltage of the node e has the swing width of the 2VDD level. Also,because the swing width of the node d becomes equal to that of the nodee by the capacitor C5, the voltage of the node d swings from the VDDlevel to the 3VDD level. The NMOS transistor N5 is turned on by thevoltage of the node d which swings in this manner, so as to transfer thevoltage of the node b to the node f, thereby causing the voltage levelof the node f to become the 2VDD level. Then, the node f is pumped tothe 3VDD level by the pumping signal with the swing width of the VDDlevel from the swing width controller 104 of the fourth pumping circuit50.

Meanwhile, the NMOS transistors N10 and N11 are turned on by the voltageof the node d pumped to the 3VDD level. As a result, the node g isprecharged to the VDD level, and the voltage of the node f istransferred to the node H, thereby causing the node h to be prechargedto the 2VDD level. At this time, the node g is pumped to the 2VDD levelby the pumping signal with the swing width of the VDD level from theswing width controller 105. Then, the PMOS transistor P2 is turned on bythe signal from the node g precharged to the 2VDD level, so as to pullthe node i up to the 2VDD level, and the NMOS transistor N12 is turnedon by the enable signal OSCB_T to pull the node i down to the groundlevel. As a result, the voltage of the node i has the swing width of the2VDD level. Thereafter, the swing width of the node i is transferred tothe node h through the capacitor C7, so that the voltage of the node hswings from the 2VDD level to the 4VDD level. The NMOS transistor N6 isturned on by the voltage of the node h which swings in this manner, soas to transfer the voltage of the 3VDD level of the node f to the nodej. Consequently, a high voltage VPP pumped to the 3VDD level isoutputted at the node j.

As described above, in order to improve pumping capability under thecondition of the low supply voltage VDD, the VPP tripler of the presentembodiment pumps the high voltage VPP using the swing width controllers101 to 105, each of which increases the swing width of the pumpingsignal to the 2VDD level under the condition of the low supply voltageVDD. That is, the VPP tripler of the present embodiment increasespumping efficiency under the condition of the low supply voltage VDD bypumping the high voltage VPP to the 5VDD level when the supply voltageVDD is lower than the reference voltage, whereas pumping the highvoltage VPP to the 3VDD level when the supply voltage VDD is higher thanor equal to the reference voltage. This can be seen from FIG. 4 which isan output waveform diagram of the VPP tripler according to the presentembodiment. In other words, it can be seen from FIG. 4 that the pumpingefficiency in the case of increasing the swing width of the pumpingsignal PCAP0, PCAP1, PCAP2 or OSC_T to the 2VDD level under thecondition of the low supply voltage VDD using each of the swing widthcontrollers 101 to 105 of the present disclosure is higher than that inthe case where the swing width is the VDD level. Although the swingwidth control circuit of the present disclosure has been disclosed inthe present embodiment to be used in the VPP tripler, among high voltagepumping circuits, for illustrative purposes, the present disclosure isnot limited thereto and is applicable to other conventional high voltagepumping circuits.

As apparent from the above description, the present disclosure providesa swing width control circuit and a high voltage pumping circuit usingthe same. When a supply voltage VDD is relatively low, the swing widthof a pumping signal for a pumping operation for generation of a highvoltage VPP is significantly increased, so that pumping capability canbe improved under the condition of the low supply voltage VDD.

Although examples and preferred embodiments of the present disclosurehave been provided for illustrative purposes, those skilled in the artwill appreciate that various modifications, additions and substitutionsare possible, without departing from the scope and spirit of thedisclosure as disclosed in the accompanying claims. For example,elements and/or features of different examples and illustrativeembodiments may be combined with each other and/or substituted for eachother within the scope of this disclosure and appended claims.

What is claimed is:
 1. A high voltage pumping circuit comprising: afirst pumping circuit including a precharge circuit configured toprecharge a first node, a first swing width controller configured toreceive a first inputted pumping signal having a first swing width andoutput a first pumping signal having a second swing width for pumping ofa voltage of the first node when a supply voltage is lower than apredetermined reference voltage, and a first swing width holding deviceconfigured to maintain a swing width of the first node to be equal tothat of the first pumping signal from the first swing width controller;a second pumping circuit including a first precharge device configuredto precharge a second node in response to a signal from the first node,a second swing width controller configured to receive a second inputtedpumping signal having the first swing width and output a second pumpingsignal having the second swing width for pumping of a voltage of thesecond node when the supply voltage is lower that the predeterminedreference voltage, and a second swing width holding device configured tomaintain a swing width of the second node to be equal to that of thesecond pumping signal from the second swing width controller; and afirst transfer device configured to transfer the voltage of the secondnode in response to a first transfer control signal which is distinctfrom a signal at the second node, wherein the second swing width islarger than the first swing width.
 2. The high voltage pumping circuitas set forth in claim 1, wherein the second swing width is set to twicethe first swing width.
 3. A high voltage pumping circuit comprising: afirst pumping circuit including a precharge circuit configured toprecharge a first node, a first swing width controller configured toreceive a first inputted pumping signal having a first swing width andoutput a first pumping signal having a second swing width for pumping ofa voltage of the first node, and a first swing width holding deviceconfigured to maintain a swing width of the first node to be equal tothat of the first from the first swing width controller; a secondpumping circuit including a first precharge device configured toprecharge a second node in response to a signal from the first node, asecond swing width controller configured to receive a second inputtedpumping signal having the first swing width and output a second pumpingsignal having the second swing width for pumping of a voltage of thesecond node, and a second swing width holding device configured tomaintain a swing width of the second node to be equal to that of thesecond pumping signal from the second swing width controller; a firsttransfer device configured to transfer the voltage of the second node inresponse to a first transfer control signal which is distinct from asignal at the second node, wherein the second swing width is larger thanthe first swing width, in accordance with a level of a supply voltage; athird pumping circuit including a second precharge device configured toprecharge a third node in response to the signal from the first node, athird swing width controller configured to receive a third inputtedpumping signal having the first swing width and output a third pumpingsignal having the second swing width for pumping of a voltage of thethird node, and a third swing width holding device configured tomaintain a swing width of the third node to be equal to that of thepumping signal from the third swing width controller; and a firstcontrol signal generator including a third precharge device configuredto precharge a fourth node in response to the signal from the firstnode, a first swing width changer configured to change a swing width ofa signal from the third node, and a fourth swing width holding deviceconfigured to maintain a swing width of the fourth node to be equal tothat of an output signal from the first swing width changer to generatethe first transfer control signal.
 4. The high voltage pumping circuitas set forth in claim 3, wherein the first swing width changer outputs asignal swinging between a ground voltage and a high-level voltage of thesignal from the third node.
 5. The high voltage pumping circuit as setforth in claim 3, wherein the first swing width changer comprises: apull-up device connected between the third node and a fifth node, thepull-up device pulling the fifth node up in response to the supplyvoltage; and a pull-down device connected between the fifth node and aground voltage, the pull-down device pulling the fifth node down inresponse to an enable signal.
 6. The high voltage pumping circuit as setforth in claim 3, wherein each of the first to third swing widthcontrollers comprises: a supply voltage detector configured to generatea control signal having a first level when the supply voltage is higherthan or equal to a predetermined reference voltage, and having a secondlevel when the supply voltage is lower than the reference voltage; and aswing width selector configured to receive the control signal and therespective inputted pumping signal of the swing width controller, andoutput said respective inputted pumping signal when the control signalhas the first level, and output the respective pumping signal when thecontrol signal has the second level.
 7. The high voltage pumping circuitas set forth in claim 6, wherein the swing width selector comprises: asignal input unit configured to pull a fifth node up and transfer therespective inputted pumping signal to a sixth node, when the controlsignal has the first level, and transfer the respective inputted pumpingsignal to the fifth node when the control signal has the second level;and a signal processor connected between the fifth node and the sixthnode, the signal processor generating the respective pumping signal andoutputting it to the sixth node, when the respective inputted pumpingsignal is transferred to the fifth node.
 8. The high voltage pumpingcircuit as set forth in claim 7, wherein the signal input unitcomprises: first and second transfer gates selectively turned on inresponse to the control signal; and a pull-up device configured to pullthe fifth node up in response to the control signal, wherein the firsttransfer gate transfers the respective inputted pumping signal of theswing width controller to the fifth node, and the second transfer gatetransfers the respective inputted pumping signal to the sixth node. 9.The high voltage pumping circuit as set forth in claim 7, wherein thesignal processor comprises: a first capacitor connected between thefifth node and a seventh node; a buffer connected to the fifth node; asecond capacitor connected between an output terminal of the buffer andan eighth node; a first pull-up device connected between the seventhnode and the supply voltage, the first pull-up device pulling theseventh node up in response to a signal from the eighth node; a secondpull-up device connected between the eighth node and the supply voltage,the second pull-up device pulling the eighth node up in response to asignal from the seventh node; a first transistor connected between theeighth node and a ninth node, the first transistor being turned on inresponse to a signal from the fifth node; and a third capacitorconnected between the ninth node and the sixth node.
 10. The highvoltage pumping circuit as set forth in claim 9, wherein the firstpull-up device and the second pull-up device are NMOS transistors andthe first transistor is a PMOS transistor.
 11. The high voltage pumpingcircuit as set forth in claim 9, wherein the signal processor furthercomprises a second transistor connected between the ninth node and aground voltage, the second transistor being turned on in response to thesignal from the fifth node.
 12. The high voltage pumping circuit as setforth in claim 3, wherein the first to fourth swing width holdingdevices are capacitors.
 13. The high voltage pumping circuit as setforth in claim 3, wherein the precharge circuit comprises: a fourthprecharge device connected between the supply voltage and the firstnode, the fourth precharge device precharging the first node in responseto the supply voltage; and a fifth precharge device connected betweenthe supply voltage and the first node, the fifth precharge deviceprecharging the first node in response to the signal from the thirdnode.
 14. The high voltage pumping circuit as set forth in claim 3,further comprising: a fourth pumping circuit including a fourth swingwidth controller configured to receive a fourth inputted pumping signalhaving the first swing width and output a fourth pumping signal forpumping of a voltage of a fifth node to which the voltage of the secondnode is transferred through the first transfer device, and a fifth swingwidth holding device configured to maintain a swing width of the fifthnode to be equal to that of the pumping signal from the fourth swingwidth controller; and a second transfer device configured to transferthe voltage of the fifth node in response to a second transfer controlsignal, wherein the fourth swing width controller receives the fourthinputted pumping signal having the first swing width and generates thefourth pumping signal having the second swing width larger than thefirst swing width of the fourth inputted pumping signal when the supplyvoltage is lower than a predetermined reference voltage.
 15. The highvoltage pumping circuit as set forth in claim 14, further comprising: afifth pumping circuit including a fourth precharge device configured toprecharge a sixth node in response to a signal from the fourth node, afifth swing width controller configured to receive a fifth inputtedpumping signal and output a fifth pumping signal for pumping of avoltage of the sixth node, and a sixth swing width holding deviceconfigured to maintain a swing width of the sixth node to be equal tothat of the pumping signal from the fifth swing width controller; and asecond control signal generator including a fifth precharge deviceconfigured to precharge a seventh node in response to the signal fromthe fourth node, a second swing width changer configured to change aswing width of a signal from the sixth node, and a seventh swing widthholding device configured to maintain a swing width of the seventh nodeto be equal to that of an output signal from the second swing widthchanger to generate the second transfer control signal.
 16. The highvoltage pumping circuit as set forth in claim 15, wherein the secondswing width changer comprises: a pull-up device connected between thesixth node and an eighth node, the pull-up device pulling the eighthnode up in response to the supply voltage; and a pull-down deviceconnected between the eighth node and a ground voltage, the pull-downdevice pulling the eighth node down in response to an enable signal.